Even if he can't remember the exact details of that pendant being left in his hands, what Shinji can remember is the crushing feeling of finality that had come on the heels of him receiving it. If what Kai has is actually his memory about it, then he already knows that's bad. Bad enough to leave him doubled over in the kitchen, easily. Probably even worse, if he let them linger too much longer.

"I'm sorry," he squeaks out, his throat suddenly feeling totally dry. Just as he had feared - something he very much wouldn't have wanted to get out has very probably done just that, and to the person he'd least want to subject it to in the first place. Ah. This really is bad. "I'll take it back, in just a minute."

Just let him give Kai his back, first. Sorry you'll have to deal with Shinji's memories on top of yours for a little bit, Kai, but hopefully this hand carefully reaching out once more and sinking its fingers into his hair is a halfway decent consolation.